XML 182 R159.htm IDEA: XBRL DOCUMENT v3.21.1

Pledged assets - Certain Assets Provided as Collateral Mainly for Long-term Bank Loans and Leases (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement [LineItems]
Purpose	Lease and bank loan
Non-current financial assets at amortized cost	$ 48,319	$ 68,450
Assets pledged as collateral for liabilities	$ 11,505,888	8,723,029
Land [member]
Statement [LineItems]
Purpose	Bank loan
Property, plant and equipment, net	$ 452,738	452,738
Buildings [member]
Statement [LineItems]
Purpose	Bank loan
Property, plant and equipment, net	$ 4,092,287	4,095,929
Machinery and equipment [member]
Statement [LineItems]
Purpose	Bank loan
Property, plant and equipment, net	$ 6,912,544	$ 4,105,912

X

- Definition

The fair value of collateral held that is permitted to be sold or repledged in the absence of default by the owner of the collateral. [Refer: At fair value [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 15
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_15_a&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_AssetsHeldAsCollateralPermittedToBeSoldOrRepledgedAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The amount of property, plant and equipment pledged as security for liabilities. [Refer: Property, plant and equipment]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2020-01-01
-Paragraph 74
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_74_a&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_PropertyPlantAndEquipmentPledgedAsSecurity
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Description of borrowings purpose.

+ References

No definition available.

+ Details

Name:	imos_DescriptionOfBorrowingsPurpose
Namespace Prefix:	imos_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Non-current pledged collateral assets at amortised cost.

+ References

No definition available.

+ Details

Name:	imos_NoncurrentPledgedCollateralAssetsAtAmortisedCost
Namespace Prefix:	imos_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	imos_StatementLineItems
Namespace Prefix:	imos_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=ifrs-full_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=ifrs-full_BuildingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=imos_MachineryAndEquipment1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: